Remotely operated robotic arms (often called “manipulators” or “slave arms”) are used to carry out automated or unplanned tasks requiring precise dexterity in locations inaccessible to humans due to environmental constraints. Typical environmental constraints are any factors deemed too hazardous for human access, such as work site radiation levels and atmospheric pressures beyond safe human limits. Because of these environmental constraints, unknown worksite conditions, forces within the operating environment and the unknown or unstable nature of the environment, articulated control in the form of joint positions is usually preferable to Cartesian, selective compliant articulated robot arm (SCARA), or Delta control.
Among the clear and pressing needs for remotely operated robotic systems, perhaps the most urgent is to limit the impact of an environmental disaster, whether a natural disaster or human-induced. Such systems are particularly useful where exposure time is paramount in mitigating effects on the environment and on people engaged in necessary repairs, such as the Fukushima Daiichi nuclear disaster and the Hercules 265 natural gas blowout disaster, or where human intervention is not even possible, such as the subsea Deepwater Horizon oil spill disaster.
Most controls for existing remotely operated systems require the system operator, be it human or automated, to control the robotic manipulator without the benefit of physical feedback beyond haptics or visual indicators. However, such systems have major disadvantages. The most obvious performance inefficiency of current technology is the inability of the manipulators to react quickly and accurately enough to operator input intent and the inability of operators to transpose the intended motion through existing control inputs. Thus, there is a need for a remotely operated manipulator system that provides better control inputs, which, in turn, improve translation of operator intent into actual motion of the manipulator and also improve the operator's sensation of what the manipulator is encountering in the remote environment. Similarly, there is a need for a system that emulates human motions and perceptions, such that it is easier, more intuitive and more effective for human operators to use.
Currently available remotely operated robotic systems have several specific drawbacks. First, current technology lacks effective manipulator (sometimes referred to as a “slave arm”) feedback through reaction forces on the controller input mechanisms of the system. Moreover, most systems require the use of different input mechanisms for different control modes of the manipulators. Also, switching control modes in currently available systems typically interrupts input motion, disrupts operation, and leads to less effective manipulator operation.
Accordingly, there is a need for remotely operated manipulator systems and methods that provide better control inputs so as to improve translation of operator intent into actual motion of the manipulator. There is also a need for remotely operated manipulator systems and methods that facilitate slave manipulator feedback to the “master” controller arm of the input system. There is a further need for remotely operated manipulator systems and methods that use the same input mechanisms to control all manipulator joints simultaneously regardless of the control mode. Finally, there is a need for remotely operated manipulator systems and methods that seamlessly switch control modes without interrupting input motion during operation.